GUANGZHOU -- Chinese researchers have found that the chemical energy instantaneously released by crustal activities like earthquakes can serve as an "alternative fuel" to sunlight for subterranean microorganisms.

This latest finding reveals an important energy source for deep-Earth ecosystems and also aids in the search for potential subterranean life on planets like Mars and Europa.

The study, led by researchers from the Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, was recently published in the journal Science Advances.

In the dark depths beyond human sight, 95 percent of the Earth's prokaryotic organisms reside, accounting for about 19 percent of the total biomass on Earth. These life forms cannot obtain organic matter synthesized through photosynthesis, and how they obtain energy has long been a mystery in the scientific community, according to the researchers.

After conducting simulations of faulting activities several kilometers underground, the team discovered that when rocks fracture and create fresh surfaces, the newly broken chemical bonds come into immediate contact with water. This interaction generates a substantial amount of hydrogen and hydrogen peroxide. This leads to the oxidation and reduction cycles of iron, continuously releasing electrons in the process.

These electrons further flow between essential elements for life, such as carbon, sulfur, and nitrogen, forming an invisible "subterranean power grid" that provides readily available energy for microorganisms, said the team.

Based on the study, the researchers said that in future missions to detect extraterrestrial life, it is essential to pay special attention to searching for oxidized and reduced substances near fault zones, which could be crucial conditions for the existence of life.